1. Field of the Invention
The invention pertains to a piston-cylinder assembly with a braking device according to the introductory clause of claim 1.
2. Description of the Related Art
U.S. Pat. No. 6,007,057 discloses a piston-cylinder assembly comprising a cylinder, in which a piston rod is installed with freedom of axial movement. The cylinder is filled with gas, which exerts an ejection force on the piston rod. This force is associated with a certain maximum excursion speed of the piston rod. In cases where external forces cause the speed of this movement to exceed the maximum excursion speed, a braking device becomes active, which limits the speed to a desired value. A piston, which divides the cylinder into two working spaces, is attached to the piston rod; the two spaces are connected by at least one flow-through opening. When the rod moves at a speed greater than that defined for it, the dynamic pressure in the working space causes a cover disk to close off the flow-through opening(s) at least partially in opposition to the forces which are trying to keep them open. The dynamic pressure in the working space assigned to the cover disk leads to an elastic deformation of the cover disk. This deformation represents a closing movement relative to the cross section(s) of the flow-through opening(s).
Valve designs can be imagined in which the top surface of the piston is not available for a cover disk. In this case, it is possible, under certain conditions, to provide a piston valve according to DE 3,923,512. This, however, leads to the new problem that there are only a few, limited possibilities for providing a properly designed flow connection between the working spaces. In addition, the design of the valve itself is already rather complicated.